完成api最后调试

backend/service.py

@@ -64,14 +64,7 @@ class CrawlerService:
                 ).values(status='processing')
                 conn.execute(upd)
             return {"urls": urls}
-from sqlalchemy import select, insert, update, and_
-from .database import db_instance
-from .utils import normalize_url
-
-class CrawlerService:
-    def __init__(self):
-        self.db = db_instance
-
+        
     def save_results(self, task_id: int, results: list):
         """
         保存同一 URL 的多个切片。
@@ -164,4 +157,5 @@ class CrawlerService:
             }
         }
 
+
 crawler_service = CrawlerService()